This invention relates generally to optical occluders suitable for use with monocular optical instrument, for blocking the vision of the user's eye that is not looking through the instrument. More particularly, this invention relates to optical occluders adapted for attachment to monocular optical instruments having a variety of shapes and sizes. Users of monocular optical instruments, including microscopes, telescopes, cameras and the like, have long recognized that closing the eye not looking through the instrument is bothersome and, over extended time periods, can be quite fatiguing. Keeping both eyes open will eliminate that fatigue, but ordinarily will cause two different images to be perceived by the brain, one image being that provided by the optical instrument and the other being of objects surrounding the instrument. Separating these two conflicting images in the brain can cause confusion, fatigue and headaches.
In the past, some monocular optical instruments have included special optical occluders for blocking the vision of the user's eye not looking into the instrument. These occluder's have typically included a generally planar, disc-shaped eye shield and an associated cylindrical collar for attachment directly to the optical instrument's eyepiece. Although generally effective in blocking the vision of the user's second eye, and thus reducing eye fatigue, the occluders have not proven to be entirely satisfactory in use.
One drawback to the optical occluders described above is that the eye shield is not fully adjustable relative to the optical axis of the optical instrument. It thus is not sized to be completely effective for users having a range of spacings between their two eyes. Another drawback is that the cylindrical collar of each occluder is adapted for use with optical instruments having just a single size and shape. Thus, each optical instrument must ordinarily be provided with a its own occluder.
It should be appreciate from the foregoing description that there is a need for an optical occluder that is adapted for attachment to monocular instruments having a variety of shapes and sizes and that can be adjusted to accommodate the specific eye spacings of a variety of users. The present invention fulfills this need.